Internal-combustion engine and method of operating the same



May 13, 1930. F. OBERHAENSLI 1,758,460

I INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING THE SAME Filed Nov. 12 192s $Sheets-Sheet 1 TH. l

A TTORNE s y 1930. F. OBERHAENSLI 1,758,460-

INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING THE SAME iled Nov. 12, 1928 3 Sheets-Sheet 2 WI TNESS 1x1 vgwv/c y 13, 1930- F. OBERHAENSLI 1,758,460

INTERNAL COMBUSTION ENGINE AND METHOD OF OPERATING THE SAME Filed Nov. 12, 1928 3 Sheets-Sheet 5 I EMF.

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, Patented May 13, 1930 UNITED STATES PATENT OFFICE) munnnrcrr OBERHAENSLI, or BREGENZ-LOGHAU, nus-ram, ASSIGNOB mo erro -I AKTIENGESELLSGHAFT, OF ZURICH, SWITZERLAND, A CORPORATION LAND INTERNAL-COMBUSTION ENGINE AND METHOD OF OPERATING THE Application filed November 12, 1928 Serial No. 318,912, and in Germany December 1, 1927.-

My invention relates to internal combustion engines and more particularly to engines adapted to employ a heavy and diflicultly volatilizable fuel which is sprayed;- under pressure during the compression stroke into a compression space in constricted connection with the cylinder of the engine.

It is an object of he present to provide an engine of the above indicated character which is so constructed and operated that substantially complete vaporization of the oil and practically perfect mixing of-the oil vapors with the air for supporting combustion are obtained, whereby com: plete combustion and consequently high efiiciency result.

Internal combustion engines which employ heavy oils as'fuel as now constructed may be classified either as ignition head motors or as antechamber'Diesel engines. In

' ignition head motors, in order to provide the time necessary for vaporization and mixing, the fuel is injected upon the ignition or incandescent head duringthe 'suction'stroke. High compression cannot be employed in such engines as premature ignition must be avoided. In certain types ofignition head machines in which the fuel is injected shortly before the end of the compression stroke,

the compression pressure can be increased withoutdanger of premature ignition. Such increase of compression is, however, limited because of the reduced strength of the ignition head resulting from its high heating.

In antechamber Diesel engines in which the fuel is charged into a cooled antechamber at the end of the compression stroke, the compression maybe made of as high a degree as.

desired. The antechamber of such engines is,

however, so small that only a small part of the fuel in such .chamber can find'the quantity of air necessary for combustion while the main portion of the fuel is burnt in'the compression space of the cylinder. A partial explosion first takes place in the antechamber and the unburnt fuelis forced into the compression space of the cylinder above the piston, where it-burns. Engines of this type require very high pressures in order to efiect the antechamber Diesel engines. With invention,

ghelself-ignition of the diiiicultly vaporiz able The improved internal combustion engine forming the subject-matter of the present pressures lie between 15 and 25 atmospheres. I

The high pressures common in Diesel engines are unnecessar as the ignition of the fuel is p v accomplished y means of an incandescent element. As a result of the lower pressures preferably employed by me, the mixing of fuel and air is somewhat retarded, but'I overcome this difliculty by constructing the engine in such manner that the air for combustion is divided by the incandescent body into two currents having great whirling energy, the

' fuel mixing with such currents in two sta L:

The incandescentbody is constructed 'pre erably in the form of a bell suspended in the combustion chamber, and ins aced relation thereto, the whole fuel charge eing injected by means of apump into-such bell toward the end of the-compression stroke. The interior of the incandescent bell or body is con nected 'withthe piston cylinder through a neck or constricted passageway and the inlet opening for the fuel is so arranged with respect to such neck portion that only a part of the air is forced .with the fuel stream directly into'the interior of the incandescent body, the remaining air which ultimately enters the interior of the incandescent body being first deflected about at least a portion of the exteriorsurfaoe of'this body. That portion ofthe air which enters directly, is insuflicient to'support complete combustion of the fuel within the glowing element and forms with such fuel a pro-mixture of gas and air, which mixture is rendered completely combustible or rapidly ignitable only u n addition of air which has flowed aroun 'atg least a portion of the :incand'escentbody. In the accompanyin drawings-whlch lustrate by way of example three engine having my invention embodie there"- Figs. 1 and 3 are partial longitudinal sections through. four-stroke engines; Fig.*2 is i r of a partial longitudinal section through a twostroke engine, and Fig.- {1 is a section along the line 4-4 of Fig. 3.. n

Fig. 1 shows a water cooled cylinder 1 provided with a similarly cooled cylinder head 2 in which are located two valves (3) for controlling the inlet of air and the'exhaust ofthe engine, and in which is provided a c0n1- bustion space 6 preferably of spherical outline. A piston 4 which is connected in wellknown manner to a crank-shaft (not shown) fills the space 5 almost completely at its upper dead center position. As a result, the compression forces substantially all of the air into the combustion space 6. This space is separated from the maincylinder space 5 by a neck or constricted passageway 7. A bellshaped incandescent-body 8, provided with an opening 11, is located within the space6 and'operates'both as avaporizer for the heavy oil and as an igniter for thefuel-air mixture. This incandescent body is suspended from one of the walls of thecylinder head, in a manner to provide intermediate spaces 9 and 10, and preferably so as to cover partially the neck or opening 7 and thus act as a deflector for the incoming air. The whole fuel. charge is sprayed through the openin 11 into the interior of the incandescent bo y 8 by means of a fuel nozzle 12. The bod 8 is so disposed with relation to the neck and to the fuel stream discharged by the nozzlel2-as to over lie a portion of the neck opening and thus to check the direct entry of air from the cylinder into the interior of said body 8, so that the air can reach such interior only by penetrating the stream of fuel. The overlying portion of the body 8 thus divides the incoming air into two streams or portions. One portion flows through the open neck section between the edge of the opening 11 of the incandescent body and'the cylinder wall, strikes the fuel stream, penetrates the same and is projected therewith into the interior of such incandescent body substantially without having traversed the surface of the outer wall of the incandescent body 8. This portion of the air forms with the fuel a pre-mixture of gas and air which, however, because of the low proportion of air, is not completely ignited under the conditions prevailing within the combustion space. The second portion of the air strikes the outer surface of and is deflected by the incandescent body, flows into the intermediate space 9 and thus around at least a portion of the outer surface of the incandescent body, and meets the whirling pre-mixture inair above referred to is subjected to a throttling action because of thepartial closure of 3 the neck 7 by the body 8, and as a result attains a high velocity and a violent whirling action so that as it strikes the stream of fuel it exerts a diffusive and dispersive action thereon; and that the second'portion of the air as.

it leaves the narrow intermediate space 9 rushes with a violent whirling into the en-- while the space 9 is narrow in cross-section, it presents a relatively large CI'OSS-SG'CtlOIlfll area of admission to the incoming air due to the fact that it is coextensive with the exposed outer surface of the incandescent body.

This second stream or portion of air, which has been heated and somewhat delayed in its deflected course about at leasta portion of the outer surface of the lowing element, serves to form a rapidly i ammable mixture with the ire-mixture of the first mentioned stream of an and the fuel.

The incandescent body 8 is loosely supported from the side of the cylinder head by means of a flange 13 and is so held by a cover flange 14 that it can expand freely as it .becomes heated. Upon removal of theflange 13 the body 8 can be easily removed.

The flange 13 has an opening 15 which is adapted to receive an incandescent spiral 16 or similar priming apparatus, which may be heated to incandescence by any suitable means, for igniting the mixture upon starting of the engine. This apparatus is shown as carried by the cover flange. As soon as the engine becomes warm the mixture of fuel and air is ignited by the incandescent body 8 and the auxiliary igniting apparatus may then be cut out.

In the two-stroke engine illustrated in Fig.

2, the inlet and outlet openings 18 for the air and exhaust respectively are positioned in the cylinder 1 itself. Because of this construction the combustion space 6 together with the vaporizer and incandescent body 8 may be arranged along the axis of the cylinder. The fuel stream in this type of engine is directed perpendicularly to such axis. In other respects the construction of this engine is similar to that illustrated in Fig. 1.

Fig. 3 illustrates another engine, having my invention applied thereto, 1n a manner similar to that shown in Fi 1, but having a flat top piston, instead 0 the round top piston illustrated in Figs. 1 and 2. Fig. 4,

while a cross-section only of Fig. 3, serves to illustrate the construction of Figs. 1 and 2 of which therefore no crosssectional views are shown,

The method of forming the explosive mixture in accordance with my invention makes it possible to utilize, even at compression ratios under 1 :10, heavy oils such as have otherwise been capable of use only in Diesel en-v gines, and to produce intimate admixture thereof with air. The explosi'tion pressuresin my improved engine may be far below the maximum pressures of Diesel engines and mayapproximate the pressures common in ordinary gas engines. The consumption of fuelis not appreciably higher than that of Diesel engines.

As the gas-fuel mixture produced by my invention is an intimate one, my improved engine may operate at the high speeds which are common in ordinary gas engines. My en-- gi-ne can therefore be run as a high speed motor and is thus adapted for the driving of automobiles and aeroplanes. Very high eificiency is obtained with my improved engine because the combustion is complete and no unburnt fuel is carried off by the exhaust. A further-important feature of my invention is that the body 8, which acts both as a vaporizer andan igniter, remains completely clean and does not become coated with a layer of carbon. Because of the fact that the fuel is not directed upon the piston and into the cylinder, the latter do not become covered with unburnt residual matter.

y The spherical form of the combustion space 6 and of the incandescent body has a favor able and important influence upon the production of whirling within the air streams and thus upon the completion of the mix ture of air and fuel. however, that the incandescent body 8 may assume otherv forms than the spherical and it is to be understood that where It will be obvious,

in the claims I employ the term bell-shaped body the same is to be construed generically as including all suitable forms of hollow bodies having an opening to receive a stream of fuel and air and capable of being so positioned within the combustion space that an intermediate space is provided between such body and the walls of the cylinder head.

My invention may be employed with equal advantage 'in vertical and in horizontal engines. Other variations from the specific forms shown and described may be resorted to withinthe scope of the appended claims without departing from .the spirit of my invention. I

I claim:

1. A heavy oil motor comprising a cylinder, a piston slidable therein, an air inlet valve, a hollow member associated with said cylinder and defining a compression space into which a charge of air is adapted to be forced and compressed during the compression stroke of the piston, said space communicating with the interior of said cylinder through a constricted passageway, a bellshaped body provided with an opening and positioned within said member'at least par-.

tially in spaced relation thereto, whereby'an intermediate space between said body and said member is formed, and a fuel nozzle arranged to spray 'a stream of fuel into the in disposed with respect to said passageway as to divide the current of air into two streams such that part of the current of air enters directly with said fuel into said body and part is deflected into the intermediate space about said body, whereby a pre-mixture of air and fuel comprising a. mixture slow to ignite is first formed in said body, said pre-mixture becoming rapidly inflammable on mixing with the air streaming around said body throu h said intermediate space.

2.v heavy oil motor as set forth in claim 1 wherein said bell-shaped body is so positioned as partially to cover said passageway, whereby the portion of the air entering with the fuel into the interior of said body attains a high velocity and is set into violent whirlg- 3. A heavy oil motor as set forth in claim 1, wherein said fuel nozzle and said bell-shaped body are-sodisposed with respect to each other that the portion of the air flowing through said passageway 'and'into said body must penetratethfe stream of fuel directed by said nozzle into the opening of said body.

4. -A heavy oil motor as set forth in claim 1, wherein said bell-shaped body at approxi mately its open end is spaced farther from the walls of said hollow member than is the opposite portion thereof, whereby an enlarged mixing space is provided into which the air streaming through said'intermediate space rushes with violent whirling motion to form the'final combustible mixture with the pre-mixture. 7

5. A heav oil motor as set forth in claim 1 wherein t e interior walls of said hollow member and said incandescent body are sub- I der, 9. piston slidable therein, an air inlet valve, a hollow member associated with said cylinder and defining a compression space into which a charge of air is adapted to be forced and compressed during the compression stroke of the piston, said space communicating with the interior of said cylinderthrough a constricted passageway, a fuel nozzle arranged to spray a streamof fuel into said space, and a deflector partiall obstructing said passageway and arrange to divide the air flowing through said passageway into two streams, one of said streams being d1- rected toward the fuel stream at a substantial I angle thereto'to form a-pre-mixture therewith, said deflector being positioned to initially deflect the second alr stream awayfrom said fuel stream during the formation of the pre-mixture and beingof such shape as ult1- mately to direct such, said second air stream into said pre-mixture, whereby a final combustible mixture is formed. I

1o 8. The method of operating an internal combustion engine having an incandescent ignition element within its combustion space and to which separate charges of air and fuel are fed, which comprises first mixing said fuel within said combustion space during the compression stroke with a portion of the air charge to form a pro-mixture therewith, and then heating the remaining air and adding to such mixture the remaining air to form the go final explosive charge, toward the end of the compression stroke.

9. The method of operating 'an internal combustion engine having an incandescent ignition element within its combustion space,

which comprises spraying a charge of fuel into such space during the compression stroke of the plistonwhile simultaneously com ressingac arge of air toward said space, 'viding such air into two portions, one of said portions being directed toward said space to mix with said fuel to form a pre-mixture therewith, and heating and directing the remaining air by a separate path toward said mixture to form a rapidly inflammable mixture 36 therewith.

10. The method of operating an internal combustion engine having an incandescent ig: n1t1on element in 1ts combustion space, and

such s ace in constricted connection with the 49 cylin er of the engine, which comprises I spraying a stream of li uid fuel against said incandescent element to vaporized thereby, compressing a charge of air duri-n the compression stroke of said piston and directing the resulting stream of air "in suchmanner that a portion thereof impinges a ainst said fuel stream at a substantial ang e'thereto,

whereby said rtion of the air is carried along with sai fuel and forms a pro-mixture 50 with the fuelvapors, and heating and imparting a whirling motion to the remainder of the charge of air and directing thesame by a difierent path toward said pre-mixture to form a final rapidly inflammable mixture 1 r therewith.

FRIEDRICH OBERHAENSLL 

